1. Field of the Invention
The present invention is directed in general to the field of semiconductor devices. In one aspect, the present invention relates to shallow trench isolation regions which electrically isolate semiconductor active regions.
2. Description of the Related Art
As device performance becomes more and more demanding, semiconductor devices are formed with shallow trench isolation (“STI”) regions which form improved field isolation structures as compared to conventional local oxidation of silicon (“LOCOS”) techniques. However, the dielectric material used to form isolation trench regions can be substantially eroded during post-trench processing of the active area (e.g., gate oxide and gate poly formation), resulting in divots and recesses in the STI regions that create adverse parasitic sidewall devices (e.g., an unwanted sidewall parasitic MOSFET) adjacent to the active areas of an integrated circuit (IC). In addition, divots and recesses formed in the STI regions can cause gate wrap around and gate oxide leakage. Another drawback with conventional STI regions is that oxygen diffusion from the STI regions can increase the threshold voltage of narrow width high-k gates which use Hf02 gate dielectric layers.
Accordingly, a need exists for an improved shallow trench isolation region and associated semiconductor manufacturing process that address various problems in the art that have been discovered by the above-named inventors where various limitations and disadvantages of conventional solutions and technologies will become apparent to one of skill in the art after reviewing the remainder of the present application with reference to the drawings and detailed description which follow, though it should be understood that this description of the related art section is not intended to serve as an admission that the described subject matter is prior art.
It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the drawings have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements for purposes of promoting and improving clarity and understanding. Further, where considered appropriate, reference numerals have been repeated among the drawings to represent corresponding or analogous elements.